Different Types Of Ecosystems Research Articles

A portable infrared laser spectrometer for flux measurements of trace gases at the geosphere–atmosphere interface

A portable infrared laser absorption spectrometer named SPIRIT (SPectromètre Infra-Rouge In situ Troposphérique) has been set up for the simultaneous flux measurements of trace gases at the geosphere–atmosphere interface. It uses a continuous wave distributed feedback room temperature quantum cascade laser and a patented new optical multi-pass cell. The aim of SPIRIT field studies is to get a better understanding of land and water bodies to atmosphere exchange mechanisms of greenhouse gases (GHG). The analytical procedures to derive concentrations and fluxes are described, as well as the performances of the instrument under field conditions. The ability of SPIRIT to assess space and time dependence emissions of two GHG—nitrous oxide (N2O) and methane (CH4)—for different types of ecosystems is demonstrated through in situ measurements on peatland, on fertilized soil, and on water body systems. The objectives of these investigations and preliminary significant results are reported.

Across ecosystem comparisons of size structure: methods, approaches and prospects

Understanding how ecological communities are structured and how this may vary between different types of ecosystems is a fundamental question in ecology. We develop a general framework for quantifying size‐structure within and among different ecosystem types (e.g. terrestrial, freshwater or marine), via the use of a suite of bivariate relationships between organismal size and properties of individuals, populations, assemblages, pair‐wise interactions, and network topology. Each of these relationships can be considered a dimension of size‐structure, along which real communities lie on a continuous scale. For example, the strength, slope, or elevation of the body mass‐versus‐abundance or predator size‐versus‐prey size relationships may vary systematically among ecosystem types. We draw on examples from the literature and suggest new ways to use allometries for comparing among ecosystem types, which we illustrate by applying them to published data. Finally, we discuss how dimensions of size‐structure are interconnected and how we could approach this complex hierarchy systematically. We conclude: (1) there are multiple dimensions of size‐structure; (2) communities may be size‐structured in some of these dimensions, but not necessarily in others; (3) across‐system comparisons via rigorous quantitative statistical methods are possible, and (4) insufficient data are currently available to illuminate thoroughly the full extent and nature of differences in size‐structure among ecosystem types.

New Approach for Evaluation of a Watershed Ecosystem Service for Avoiding Reservoir Sedimentation and Its Economic Value: A Case Study from Ertan Reservoir in Yalong River, China

A model was established to simulate an ecosystem service of avoiding reservoir sedimentation and its economic value based on the process of sediment delivery in a watershed. The model included fabricating the watershed of the study reservoir. The sediment retention coefficient of different land cover types were used to simulate the spatial patterns of the annual quantity of the sediment that were prevented from entering the reservoir by the vegetation in each cell followed the flow path in watershed. The economic value of the ecosystem service in this model was determined by the marginal cost of reservoir desilting. This study took the Ertan reservoir as an example. The results showed that most eroded soil was intercepted by different types of ecosystems in the process of sediment delivery in a watershed. The region with a higher quantity of sediment retention was around the reservoir. The absolute quantity of average sediment retention in forestland was lower, so the sediment retention ability of forestland failed to be brought into fullest play in watershed.

Lessons from the timberline ecotone in the Central Tyrolean Alps: a review

As one of the most conspicuous boundaries between different types of ecosystem, the alpine timberline has attracted the interest of researchers in Innsbruck for more than 85 years. It is evident that the tree life form here reaches its absolute limit and is constrained by the harsh environment. However, the nature of constraints is less obvious and requires detailed ecophysiological analyses as exemplified in this review, which concentrates on the Central Tyrolean Alps. After focusing on the timberline environment, effects of elevation on the water relations and the CO2 gas exchange of timberline-associated conifer species will be outlined towards conclusions on tree growth and treeline fluctuations. Presently, temperature is suggested to be the key environmental factor in determining the transition from forests to alpine shrub and grassland. As many physiological aspects are influenced directly or indirectly by the temperature regime at the alpine timberline, tree life at the timberline exists close to a number of physiological limits which interact to determine the position of the alpine timberline and modulate the upper boundary of tree life. Nevertheless, understanding of the altitude of the treeline must also consider seedling establishment, especially when evaluating treeline advances and global change effects in a changing environment.

Nature 2000 Cusma Site Heteroptera

The biological material was collected during 2008 and 2009. In the studied area we have revealed a number of 533 Pentatomoidea, belonging to 37 species and 9 families. The majority of species (17) belongs to the Pentatomidae Family. 
 The researches were made within 7 different types of ecosystems: Valea Bârgăului riverside coppice, Valea Budacu riverside coppice, Budacu spruce, Tăul Zânelor pasture, Piatra Fântânele hayfield, Colibiţa hayfield, Budacu hayfield. Most species (25) live within Piatra Fântânele hayfield. The most abundant species are polyphagous. Dolycoris baccarum, Carpocoris purpureipennis, Eurygaster testudinaria and Rhopalus parumpunctatus were collected from all 7 types of ecosystems.

Ostracod (Crustacea) colonization of a native and a non-native macrophyte species of Hydrocharitaceae in the Upper Paraná floodplain (Brazil): an experimental evaluation

Non-native aquatic macrophytes have invaded different types of ecosystems all over the world. The exotic submersed macrophyte Hydrilla verticillata recently invaded the Parana basin, Brazil, being recorded by the first time in the natural habitats of this river in 2005. We investigated the effects of this species on ostracod assemblages and compared the abundance, richness, and Shannon–Wiener diversity of ostracod assemblages that colonize the invading species with those that colonize Egeria najas, a native submersed species with similar architecture and physical complexity. Fragments of these two species were left for 28 days in tanks to root and grow and then they were transferred to a floodplain lake where they remained in pairs (one plant of each species; N = 7) during 30 days for colonization by ostracods. A detrented correspondence analysis was used to summarize ostracod assemblage composition. Although there were no significant differences in ostracod abundance, richness and Shannon diversity when analyzed separately, cumulative curves, which permit to eliminate effects of abundance on richness, indicated a significantly higher number of ostracod species on H. verticillata. Assemblage composition was significantly different between both plant species, as shown by the first DCA axis. Our results show that H. verticillata might provide favorable habitats for native ostracod assemblages.

Can simple be useful and reliable? Using ecological indicators to represent and compare the states of marine ecosystems

Abstract Shin, Y-J., Bundy, A., Shannon, L. J., Simier, M., Coll, M., Fulton, E. A., Link, J. S., Jouffre, D., Ojaveer, H., Mackinson, S., Heymans, J. J., and Raid, T. 2010. Can simple be useful and reliable? Using ecological indicators to represent and compare the states of marine ecosystems. – ICES Journal of Marine Science, 67: 717–731. Within the IndiSeas WG, the evaluation of exploited marine ecosystems has several steps, from simple binary categorization of ecosystems to a more-complex attempt to rank them and to evaluate their status using decision-tree analyses. With the intention of communicating scientific knowledge to the public and stakeholders, focus is on evaluating and comparing the status of exploited marine ecosystems using a set of six ecological indicators and a simple and transparent graphic representation of ecosystem state (pie charts). A question that arose was whether it was acceptable to compare different types of marine ecosystems using a generic set of indicators. To this end, an attempt is made to provide reference levels to which ecosystems can be objectively compared. Unacceptable thresholds for each indicator are determined based on ecological expertise derived from a questionnaire distributed to a group of scientific experts. Analysis of the questionnaires revealed no significant difference in the thresholds provided for different ecosystem types, suggesting that it was reasonable to compare states directly across different types of ecosystem using the set of indicators selected.

Ecological, anatomical and physiological traits of benthic macroinvertebrates: Their use on the health characterization of freshwater ecosystems

Ecological, anatomical, and physiological traits of benthic macroinvertebrates: their use on the health characterization of freshwater ecosystems After some studies made in Northern Portuguese freshwater ecosystems using the benthic macroinvertebrate communities for water quality evaluation, it has been possible to see that only the analysis of some characteristics allowed to distinguish different levels of environmental disturbance. The studies of some characteristics of the macroinvertebrates and the comparison with the results of the physico-chemical pa- rameters analysed show that the more disturbed the ecosystems had, the lower dissolved oxygen concentration and organisms with greater independence from this concentration. The objective of this work is to define groups of organisms, attending to some of their characteristics that are related to getting oxygen. The groups were defined through bibliographic information and from direct observation of their behaviour. The ability of these groups to distinguish different types of ecosystems was analysed by comparison of the obtained results on their distribution in a group of sampling sites located along gradients of contamination, with the results obtained by the calculation of biological indices, descriptive metric analyses of the community, and the water chemical quality. After this study, it is possible to say that the results obtained with the use of respiratory groups can be more informative than that obtained with the analysis of the physico-chemical parameters or other biological parameters.

Soil and decomposer responses to grazing exclusion are weak in mountain snow-beds

Most of the empirical evidence available from different types of ecosystems have shown that aboveground plant-based and belowground decomposer systems are interconnected, and change in one leads to a response in the other. We analyzed responses of the soil decomposer system and soil decomposition processes to grazing exclusion and associated vegetation changes in a mountain snowbed. These habitats are of low productivity supporting bryophyte and graminoid-rich vegetation which is grazed by the Norwegian lemming and reindeer. We measured bacteria, enchytraeids, fungi, nematodes, microbial respiration, soil nitrogen (ammonium and nitrate), and soil water content from exclosure treatment plots of 5 and 15 years, where the exclusion of grazers had led to considerable vegetation changes. Soil decomposer variables showed only weak responses to the exclosure treatments or changes in aboveground vegetation (biomass and dead organic matter). Only nematodes responded positively to the short-term grazing exclusion. This suggests that above- and belowground processes are not necessarily closely interconnected in snowbed habitats and that the decomposition of plant material is directly controlled by grazer activity.

Valuation of the ecosystem services: A psycho-cultural perspective

Valuation of ecosystems services has been a challenging issue for economists. There is a growing concern to capture the total and incremental changes in services of different types of ecosystems, mainly, due to perturbations arising from anthropogenic activities. Market-based valuation techniques have long been declared inadequate and a constructed market method such as the contingent valuation method albeit a robust tool does not seem to capture the expanse, nuances, and intricacies of many of the ecosystem services. The paper attempts to address the lacunae in valuation of ecosystem services from a psychological perspective by arguing that the common person's perception of the ecosystem is quite different from what is conceptualized by conventional economists. The paper shows how the ecological identity of individuals is revealed at various levels of the decision-making hierarchy that is, from local to regional and further onto a global level. The paper builds upon insights from psychoanalytic psychology and environmental-psychology. Further, it outlines recent research findings from experimental psychology to redefine concepts such as ecological identity, self-other dichotomy, and the fostering of identification with nature, as issues that must be embraced in the valuation of ecosystem services. Extending the idea of relational goods and reciprocity, the paper offers a deconstructed view of market forces and furthers the idea of interdisciplinary collaboration and cooperation in the valuation of ecosystem services. In this perspective the dichotomy and schism between markets, missing markets and non-markets, gets renovated and reconstructed beyond a utilitarian discourse.

Global survey of diversity among environmental saltwater Bacteriovoracaceae

Halophilic Bacteriovorax (Bx), formerly known as the marine Bdellovibrio, are Gram-negative, predatory bacteria found in saltwater systems. To assess their genetic diversity and geographical occurrence, the small subunit rRNA (ssu-rRNA) gene sequences were analysed from 111 marine, salt lake and estuarine isolates recovered from 27 locations around the world. Phylogenetic analysis of these isolates using Geobacter as the outgroup revealed eight distinct ribotype clusters each with at least two isolates. Each cluster was composed of isolates with >or= 96.5% similarity in ssu-rRNA sequences. Three single isolate outliers were observed. Many of the Bx ribotypes were widely dispersed among different types of ecosystems (e.g. cluster III was recovered from the Great Salt Lake, the Atlantic Ocean, Pacific Ocean, Chesapeake Bay and gills of aquarium fish). However, cluster V was only recovered from a single ecosystem, estuaries. Cluster V was originally detected in the Chesapeake Bay and subsequently in the Pamlico Sound/Neuse River system. Principal coordinate analysis revealed that the sequences of the isolates from different environments were distinct from each other. The results of this study reveal the saltwater Bx to be phylogenetically and environmentally more diverse than was previously known.

Emergence of community structure in terrestrial mammal-dominated ecosystems

We present a paper that combines empirical and theoretical research about the trophic organization of biological communities. Some regularities are observed in the analysis of the relationship between the trophic structure (how the species are distributed among a set of feeding groups) of a number of African large mammal communities and the type of ecosystem. Different types of ecosystems are characterized by specific patterns in the trophic structure of the mammal community. In order to explain the origin of these patterns, we propose a model defining the underlying dynamic of mammal-dominated ecosystems. The main aim of this study is to show that it is possible to obtain a dynamic explanation of those patterns. The model is shown to spontaneously define different types of structures in community organization, related to those observed. We propose a model that could help to explain the correlation between different environmental factors and the abundance or diversity of herbivores, and which establishes a general mechanism that makes it possible to understand how some rules constrain the assembly of the communities. In addition, the proposed model leads us to see how biological communities can operate in an integrated way, which allows for the acceptance of their changes on large time-scales as evolutionary. In summary, we suggest that communities are unitary structures with coherent properties that result from the self-organizing dynamic of the whole system.

Network structure and robustness of marine food webs

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 273:291-302 (2004) - doi:10.3354/meps273291 Network structure and robustness of marine food webs Jennifer A. Dunne1,4,*, Richard J. Williams2,4, Neo D. Martinez3,4 1Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, New Mexico 87501, USA 2National Center for Ecological Analysis and Synthesis, University of California Santa Barbara, 735 State St., Suite 300, Santa Barbara, California 93101-3351, USA 3Center for Applied Mathematics, 657 Frank HT Rhodes Hall, Cornell University, Ithaca, New York 14853, USA 4Pacific Ecoinformatics and Computational Ecology Lab, Rocky Mountain Biological Laboratory, PO Box 519, Crested Butte, Colorado 81224, USA *Email: jdunne@santafe.edu ABSTRACT: Previous studies suggest that food-web theory has yet to account for major differences in food-web properties of marine versus other types of ecosystems. We examined this issue by analyzing the network structure of food webs for the Northeast US Shelf, a Caribbean reef, and Benguela, off South Africa. The values of connectance (links per species2), link density (links per species), mean chain length, and fractions of intermediate, omnivorous, and cannibalistic taxa of these marine webs are somewhat high but still within the ranges observed in other webs. We further compared the marine webs by using the empirically corroborated niche model that accounts for observed variation in diversity (taxon number) and complexity (connectance). Our results substantiate previously reported results for estuarine, fresh-water, and terrestrial datasets, which suggests that food webs from different types of ecosystems with variable diversity and complexity share fundamental structural and ordering characteristics. Analyses of potential secondary extinctions resulting from species loss show that the structural robustness of marine food webs is also consistent with trends from other food webs. As expected, given their relatively high connectance, marine food webs appear fairly robust to loss of most-connected taxa as well as random taxa. Still, the short average path length between marine taxa (1.6 links) suggests that effects from perturbations, such as overfishing, can be transmitted more widely throughout marine ecosystems than previously appreciated. KEY WORDS: Food webs · Network structure · Marine ecosystems · Robustness · Connectance · Niche model · Biodiversity loss Full text in pdf format PreviousExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 273. Online publication date: June 08, 2004 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2004 Inter-Research.

Simulation of aquatic food web and species interactions by adaptive agents embodied with evolutionary computation: a conceptual framework

Individual-based and state variable-based adaptive agents (AA) are discussed regarding their relevance to different types of ecosystems. Individual-based AA proved applicable to a spatially explicit simulation of highly simplified terrestrial food webs. State variable-based AA with evolutionary computation (EC) embodied are suggested for the simulation of aquatic food webs and plankton species interactions. Embodiment of EC in AA can be achieved by evolving predictive rules (ER), differential equations (EDE) or artificial neural networks (ANN) derived from a diverse lake database. In order to provide ecosystem simulation with resilience to environmental change, agent banks can be created containing alternative agents for same species or functional groups from different lakes. State variable-based AA are currently tested for aquatic ecosytem simulation by means of a diverse lake database. It promises to overcome constraints by the rigidity of traditional lake ecosystem models.

Análise quantitativa da influência de um novo paradigma ecológico: autocorrelação espacial

The aim of this paper was to evaluate the influence of the spatial autocorrelation (absence of independence among observations gathered along geographical space) in ecological studies. For this task, an evaluation of the studies that used spatial autocorrelation analysis was carried out using the data furnished by the Institute for Scientific Information. There is a positive temporal tendency in the number of studies that used spatial autocorrelation analysis. A significant autocorrelation was detected in most studies. Moreover, scientist of several nationalities carried out these studies in different countries, with different organisms and in different types of ecosystems. In this way, it is possible to consider that the explicit incorporation of the spatial structure of natural processes, through the autocorrelation analysis, is a new ecological paradigm

Pattern of Salmonella excretion in amphibians and reptiles in a vivarium

During a period of about three years the faeces of five species of amphibians (35 individuals) and of 23 species of reptiles (103 individuals) living in one vivarium with terrariums imitating different types of ecosystems were examined for salmonellae. From 54 out of 376 faecal samples Salmonella spp. was isolated (=14%). Twenty-one different Salmonella strains were found. Salmonellae could be isolated about twice as often from animals kept under arid or mesic conditions than from animals living in humid or aquatic environments although this was not statistically significant. Statistically significant for the rate of Salmonella excretion was the animals' diet and the class the animals are belonging to. Animals feeding on mice (p=0.04) and reptiles in general (p=0.04) were more commonly excreting Salmonella. Duration of stay was also a significant factor (p=0.0005), whereby the relative risk for Salmonella excretion increased with the factor 2.91 per year during the investigation period. Salmonella strains were not necessarily transferred among animals living in the same terrarium or among the inhabitants of different terrariums. The pattern of Salmonella excretion was generally fragmentary. The outsides as well as the insides of the walls of the terrariums were also tested for salmonellae several times, but salmonellae have never been isolated.

Linking spatio-temporal dynamics of earthworm populations to nutrient cycling in temperate agricultural and forest ecosystemsThe 7th international symposium on earthworm ecology · Cardiff · Wales · 2002

Numerous laboratory and small plot-scale studies have highlighted the importance of earthworm populations in decomposition and nutrient cycling. However, the simple scaling up of such results to explain conditions on a large field scale, across agricultural landscapes under varied management scenarios, or across landscapes made up of different types of ecosystems (agricultural, grassland, forest), is very much constrained by a lack of information about the spatiotemporal distribution of earthworm populations. This study documents the spatiotemporal variation in earthworm populations in temperate ecosystems. A mixed deciduous forest, grass-dominated hayfield and corn agroecosystem were each fitted with a single 50 m × 50 m sampling grid, consisting of twenty-five 10 m × 10 m cells. Earthworms were collected at distinct single georeferenced locations in each of the 25 cells. Locations varied according to the sampling date (May, July or September). The earthworms collected by hand-sorting and formalin extraction, were first separated by species, then counted and weighed. The soil characteristics (temperature and moisture content, extractable nutrients, organic matter, pH) were also assessed for each time and location. Geostatistical and correlation analyses served to generate spatial maps of earthworm populations and to assess which soil factors most closely paralleled the numerical distribution of earthworms. This provided some insight into small-scale heterogeneity in earthworm populations, possibly allowing for the future extrapolation of laboratory and controlled field study results to larger scales, and in turn a more accurate estimation of the role of earthworms in nutrient cycling at the ecosystem and landscape levels.

Linking spatio-temporal dynamics of earthworm populations to nutrient cycling in temperate agricultural and forest ecosystems: The 7th international symposium on earthworm ecology · Cardiff · Wales · 2002

Numerous laboratory and small plot-scale studies have highlighted the importance of earthworm populations in decomposition and nutrient cycling. However, the simple scaling up of such results to explain conditions on a large field scale, across agricultural landscapes under varied management scenarios, or across landscapes made up of different types of ecosystems (agricultural, grassland, forest), is very much constrained by a lack of information about the spatiotemporal distribution of earthworm populations. This study documents the spatiotemporal variation in earthworm populations in temperate ecosystems. A mixed deciduous forest, grass-dominated hayfield and corn agroecosystem were each fitted with a single 50 m × 50 m sampling grid, consisting of twenty-five 10 m × 10 m cells. Earthworms were collected at distinct single georeferenced locations in each of the 25 cells. Locations varied according to the sampling date (May, July or September). The earthworms collected by hand-sorting and formalin extraction, were first separated by species, then counted and weighed. The soil characteristics (temperature and moisture content, extractable nutrients, organic matter, pH) were also assessed for each time and location. Geostatistical and correlation analyses served to generate spatial maps of earthworm populations and to assess which soil factors most closely paralleled the numerical distribution of earthworms. This provided some insight into small-scale heterogeneity in earthworm populations, possibly allowing for the future extrapolation of laboratory and controlled field study results to larger scales, and in turn a more accurate estimation of the role of earthworms in nutrient cycling at the ecosystem and landscape levels.

Fate and bioaccumulation of isoproturon in outdoor aquatic microcosms

To gain information concerning the ecotoxicity of isoproturon (IPU) on aquatic ecosystems, six experimental ponds of 5 m3 each were studied. All the experiments were conducted during the summer over two years. Three different types of ecosystems were tested in 1994 and one type of ecosystem was selected and repeated in 1995 with three replicates. In each case, the initial concentration of IPU contamination was set at 10 microg/L. The IPU concentration was determined in the water column and in different species (mainly plants) of the microcosms. A first-order kinetic decrease in IPU concentration was observed in 1994, with half-life ranging from 15 to 35 d, depending on the microcosms. This relatively fast decrease was also confirmed in 1995, but it reached a constant value after two months. A high variability of the IPU concentration was observed in exposed plants, with bioconcentration factors ranging from 100 to 1,200 with large coefficients of variation. The observed plant bioconcentration factors are higher than those predicted by usual numerical models, probably due to the specific binding of IPU on one protein of the photosynthetic apparatus. Our data show that bioconcentration does not occur in mollusks but is important in photosynthetic organisms. Plant bioconcentration and microbial biodegradation are the main processes involved in the IPU decay in our outdoor aquatic microcosms.

Indicators for biodiversity assessment in Costa Rica

Indicators used by the “Harmony with Nature” chapter of the “4th State of the Nation Report” (SOTNR) for monitoring biodiversity in Costa Rica were reviewed in order to assess its value as a monitoring tool. They were compared with the framework and indicators proposed by the Subsidiary Body on Scientific, Technical and Technological Advice (SBSTTA) of the Convention on Biological Diversity of which Costa Rica is a party. The SOTNR included state, pressure and use-response indicators for four different types of ecosystems: forest, marine-coastal, freshwater and agricultural systems. However, very few indicators related to species and genetic level were available. More information and indicators for forest and agricultural systems existed than for other types of ecosystems. Some indicators — ecosystems quantity, population density or infrastructure — were not desegregated by type of ecosystem. A main limitation of the report was the non-availability of ecosystem quality indicators. Suggestions are made for the inclusion of a fuller set of indicators to ensure that impact and sustainability can be monitored comprehensively at different levels of scale.